A great number of processes and devices for preparing liquid to thin pulpy media, have become known. These processes and devices are used mainly in the areas of wastewater treatment, water preparation, and the preparation of colloidal mixtures. To produce colloidal mixtures by turbulence, especially by means of rotors, intensive mixing of the starting components is achieved. The medium processed develops a colloidal structure due to the size reduction of macroscopic granules or by binding together a plurality of molecules to form clusters. In a prior-art device of this type (West German Offenlegungsschrift No. DE-OS 32,41,011), the medium to be treated is filled from the top into a funnel-shaped container. The medium flows through the funnel from top to bottom under the effect of the force of gravity. The medium leaves the funnel through an outlet opening provided at the lower end of the funnel. This device generates a vortex-like turbulence, which is intended to bring about intense mixing of the components present in the medium, e.g., cement and water. A further improved variant of this device has also become known (West German Offenlegungsschrift No. DE-OS 33,25,952), in which a two-chamber system is used. The inner, funnel-shaped chamber again serves to turbulize the medium flowing through from top to bottom under the effect of the force of gravity, while the outer chamber serves to return the medium leaving the inner chamber to the inlet opening of the inner chamber. A rotor mounted in the vertical axis of the container is used to return the medium. The vanes of the rotor are located in the outer chamber under the outlet opening of the inner chamber, and the rotor returns the medium to the inlet opening of the inner chamber against the force of gravity.
These prior-art devices have mainly the disadvantage that the efficiency is not high enough to achieve sufficient colloidization of the treated medium within a reasonable time. Despite the fact that propellers are provided to support the turbulizing effect of the force of gravity by suction and pumping, the amount of energy introduced is too small. Another disadvantage is the fact that the medium is returned to the inlet opening of the inner chamber against the force of gravity and this is also brought about by a propeller, which is arranged on the same axis as the propeller for generating the suction effect, which is arranged in the inner chamber. The flow conditions are thus undefined, and the amounts of energy introduced partially offset each other.